The Clark's Nutcracker (Nucifraga columbiana), is a large passerine bird, in the family Corvidae. It is slightly smaller than its Eurasian relative Spotted Nutcracker (N. caryocatactes). It is ashy-grey all over except for the black-and-white wings and central tail feathers (the outer ones are white). The bill, legs and feet are also black.

It can be seen in western North America from British Columbia and western Alberta in the north to Baja California and western New Mexico in the south. There is also a small isolated population on the peak of Cerro Potosí, elevation 3,700 metres (12,200 ft), in Nuevo León, northeast Mexico. It is mainly found in mountains at altitudes of 900–3,900 metres (3,000–12,900 ft) in pine forest. Outside the breeding season, it may wander extensively to lower altitudes and also further east as far as Illinois (and exceptionally, Pennsylvania), particularly following any cone crop failure in its normal areas.

The most important food resources for this species are the seeds of Pines (Pinus sp.), principally the two cold-climate (high altitude) species of white pine (Pinus subgenus Strobus) with large seeds P. albicaulis and P. flexilis, but also using other high-altitude species like P. balfouriana, P. longaeva and P. monticola. During migrations to lower altitudes, it also extensively uses the seeds of pinyon pines. The isolated Cerro Potosí population is strongly associated with the local endemic Potosi Pinyon Pinus culminicola.

Surplus pine seed is stored, usually in the ground for later consumption, in numerous caches of 5-10 seeds each spread over a wide area--up to 20 × 20 kilometers (12.5 × 12.5 mi). The birds regularly store more than their actual needs (up to 33,000 seeds per bird!) as an insurance against seed theft by other animals (squirrels, etc.); this surplus seed is able to germinate and grow into new trees, thus the bird is perpetuating its own habitat. Closely tied in with this storage behaviour is the bird's remarkable long-term spatial memory; they are able to relocate caches of seeds with remarkable accuracy, even six months later, and even when the cache sites are buried under up to a meter (3 feet) of snow.

The diet also includes a wide range of insect prey, berries and other fruits, small mammals and occasionally flesh from carcasses. Eggs and nestlings are sometimes devoured, and peanuts and suet have become a favorite at bird tables. Food is taken both from the ground and from trees, where the Nutcrackers are very agile among the branches. The birds are able to extract food by clasping pine cones in such a way that the cones are held between one or both feet. The birds then hack the cones open with their strong bills. Rotten logs are also hacked into in order to locate large beetle grubs, and animal dung may be flipped over in search of insects.

Nesting is usually commenced in pines or other types of conifers. The nesting areas are often not on the sunny side of the trees. Nesting always occurs very early in the season. Wind protection often seems to be of more value for nest placement than sunlight is. Three eggs are the norm, and the quantity of eggs rarely exceeds or is found to be less than the said number. Incubation usually occurs from 16-18 days and the young are typically fledged by around the 22nd day. The fledglings follow their parents around for several months in order to learn the complex seed storage behavior.

The voice of this bird is extremely varied and produces many different sounds. However, the most frequent call is commonly described as khaaa-khaaa-khaaa or khraa-khraa-khraa, usually in a series of three.

This bird derives its name from the explorer William Clark. Other names include Clark's Crow and Woodpecker Crow.